Self-synchronous positioning control



July 26, 1949. G. E. SORENSEN SELF- SYNCHRONOUS POSITIONING CONTROLFiled July 13, 1946 Wow- Geovge Sofensen A fwmwurifi TTORNEY- PatentedJuly 26, 1949 SELF-SYNCHRONOUS POSITIONING CONTROL George E. Sorensen,Rockford, 111., assignor to Woodward Governor Company, Rocktord, m,

a corporation of Illinois Application July 13, 1946, Serial No. 683,298

8 Claims. i

This invention relates to a control mechanism for adjusting a pluralityof independently movable devices through the intermediary ofselfsynchronous electrical systems controllable from a remote point.

The primary object is to provide a novel mechanism for controlling theself-synchronizing systems in a novel manner to adjust all of thedevices by varying amounts or to bring all of 1the devices topredetermined corresponding posiions.

The invention also resides in the novel structural character means foreffecting the supplemental limit control.

Other objects and advantages of the inven tion will become apparent fromthe following detailed description taken in connection with theaccompanying drawing which is a schematic view and wiring diagram of aplurality of power units adapted to be governed by a positioning controlembodying the present invention.

The invention is shown for purposes of illustration incorporated in asystem for manually adjusting the speeds of a plurality of internalcombustion engines and also for automatically synchronizlng the speedone or more enginesS with that of a master engine M. Herein, the speedsof the power units are controlled by individual governors II which, inthe case of aircraft engines, eilect a speed regulation by adjusting thepitch of propellers ll driven by the engines. This may be accomplishedby applying hydraulic pressure controlled by the governor to a servomotor l2 or turning the propeller blades on their longitudinal axes.

The governor It on each slave and master engine includes a head I!driven by the engine and pivotally supporting fiyballs H which areconnected to a rod urged downwardly by an adjustable speeder spring l6and actuating a valve that regulates the flow of pressure fluid to andfrom the servo l2. Thus the governor operates automatically in a knownmanner to vary the propeller pitch and maintain the speed of the engineat a constant value determined by the adjustment of the speeder springIt. Such adjustment may be effected by turning a pinion l'l meshing witha rack on a movable abutment I! engaging the spring.

The pinion H is adapted to be turned by an electric motor I! mounted onthe governor casing and acting through speed reduction gearingterminating with a gear on the pinion shaft. The motor is the receiverof a selfsynchronous electrical system controllable either from a rotarytransmitter 2i or a transmitter 22 located at a remote point of controlsuch as the pilots cabin of an airplane. Herein, the electrical receiverI9 is of the step motor type having a permanently magnetized rotor 23adapted to occupy any one of twelve well defined angular positionsaccording to the combination of direct current potentials applied tothree sets of distributed windings 24 on the motor stator 24. When thesewindings are deenergized, the rotor will come to an abrupt stop and beheld magnetically.

The range of movement of each speed adjusting device I8 is positivelylimited as by stops in the form of screws 25 and 28 adjustably mountedon the governor casing and engageable by lugs 21 and 28 on the gear 20.The minimum speed is determined by the stop 26 while the maximum speedis limited by the stop 25. In accordance with the present invention, thestops 25 of all of the engines M and S are set for substantially thesame speed corresponding to that commonly used during take-off. Thus,when the speed adjusters l8 are positioned against their respectivestops 25, all of the engines will be brought to the same speed.

Herein the self-synchronous transmitters 2| and 22 are commutatorswitches each comprising angularly spaced segments 30 engaged bycontacts 3| which are arranged in pairs respectively connected to thedifierent polar terminals of a battery 32 through a conductor 33 and agrounded conductor. The segments 30' are connected directly to thewindings of the step motor I9 through a ground and conductors 34. Theconstruction of the step motor is such that as the switch shaft 35 turnsin one direction, the windings of the step motor will be energized insuccessive combinations causing the rotor 23 to follow the movements orthe switch shaft. Reverse operation of the motor takes place when therotor of the transmitter 2| is turned in the opposite direction.

To efiect automatic synchronizing, the speed of each slave engine S iscompared with that of the master engine M, and any difierence isutilized to turn the corresponding transmitter switch 2| in acorresponding direction and by an amount such as to correct for thespeed deviation. Such speed matching is effected by a differential motoror so-called differential Selsyn 36 comprising a three phase two polestator and a three phase two pole rotor the rotor being fast on theshaft 35. The windings 31 and 38 are e ergized. by small permanentmagnet generators camera represented diagramatically at 39 andrespectively mounted on the engines M and S and driven thereby.

with both windings of the differential motor energized and with the"engines M and S running at the same speed, the frequencies of the twocurrent sources will be identical so that the shaft of the dlfierentialmotor will not turn, and therefore, the commutator switch 2! will beidle. When the speeds of the master and slave engines are different, thefrequencies of the current supplied by the respective generators willdiffer proportionately, and the rotor of the diiierential motor willturn in a direction determined by which frequency is higher. Suchoperation of the motor and the commutator switch 2! driven thereby willcontinue until the slave engine has, by operation of the step motor i9and the speed correcting means associated therewith, been brought intosynchronism with the speed of the' master engine M.

The differential motor 36 is disabled at certain times, as during theadjustment of the engine speeds under manual control, by energization ofa relay 40. This opens switches 4i thereby disconnecting thetransmitter2| from the receiving motor l9 of the slave engine S. At the same time,switches 42 are closed to complete an electrical connection between themotor i9 and conductors 43 leading from the auxiliary commutator switch22 to the step motor of the governor on the master engine M. v

For the purpose of adjusting the" speed regulators l8 all of thegovernors l0 under manual control from the remote point, the shaft 44 ofthe common transmitter or commutator switch 22 is connected throughspeed reduction gearing to the shaft of a reversible motor 45 which runsin one direction or the other according to which of ,its windings 46 or41 is energized from the battery 32. The circuit for the winding 45 isclosed by a switch 48 when a relay 49 is energized, while the winding 41is energized by closure of a switch 50 when a relay is energized. One oftwo switches 52 will be closed when either relay 49,

5| is energized. This completes a,circuit for en- ,ergizing the relay40, thereby disconnecting the commutator switch 2i from the step motorI! .to disable the synchronizing control while connecting the step motorof all of the power units to the commutator switch 22 so as to conditionthe units for manual adjustment oi. their speeds,

The speed adjusting motor 45 is started in one direction or the other bymovement of a manually operable lever 53 to a position corresponding toa newly selected speed setting where the lever is retained as byfriction. Such movement turns one part 54 oi a follow-up cam mechanism55 to close a corresponding one of two switches 56, 51 for energizingone of the relays 49, 5!. The motor 45 is started and continues to runin the proper direction until a Iollow-upcam 58 driven through speedreduction gearing 59 and clutch 60 allows the arm St to move and openthe then closed control switch 56 or 51 whereupon the motor 45 will bestopped automatically. By correlating the various gear trains, the rangeof motion of the hand lever 53 will correspond to the range of speedadjustment of the governors l0 so that the latter will, after eachchange in the setting of the lever 53, be adjusted by its motor actuatorfor the maintenance of a corresponding engine speed.

In. response to deenergization of both or the relays 43 and'5l as thegovernors become adiusted to the new speed, the switches 52 will againbe opened. This results in deenergization of the relay so therebydisconnecting the step motors from the adjusting commutator switch 22and placing only the slave motors 88 under the control of thesynchronizing commutator switch 2|. Manual control is thus withdrawn andthe synchronizing control is restored automatically.

The clutch is of the electromagnetic friction typ having driving anddriven elements 82 and 53 connected to the motor 45 and the follow-upcam 58 respectively. The elements are spring urged into grippingengagement, thereby maintaining the driving connection between the motorand the camso long as a winding 84 remains deenergized. When the windingis energized, the clutch is released thereby interrupting the drive tothe follow-up cam 58.

The present invention contemplates bringing all of the power units M-and "S to the same predetermined speed determined by the high speedstops 25 of the respective governors to, pref erably in response tomovement of the control lever 53 to a high speed or take off position asindicated. This is accomplished in the present instance by continuingthe speed increasing operation of the adjusting motor 45 after the highspeed setting has been attained as determined by the follow-up mechanismso as to insure that the speed adjuster i8 0! all of the governors willcome against their stops.

For this purpose, an extension of the lever 53 is adapted to close a.switch 56 when the lever is moved to the take ofl position. Thiscompletes a circuit for energizing a relay 6! to close a switch 68 in anauxiliary energizing circuit 63 for the speed increasing winding 41 ofthe motor 45. This circuit includes parallel switches 12 and 13 whichare normally closed and are opened by energization of relays l4 and 15having conductors 1B and TI respectively extending to the stops 25 ofthe diflerent governors. These stops cooperate with the lugs 21 to formswitches, each or which remains open until its associated speed adjusterl8 reaches the maximum speed setting. Thus the motor winding 4'! remainsenergized until the governors of each of the engines M and 8 have beenbrought to the same speed setting at which time all of the switches 12and 13 will be opened thereby stopping the motor 45. Accuratecalibration of the different power units is thus attained under thecontrol of a device such as the hand lever 53 located remotely from then ines.

Provision is made for energizing the clutch winding 64 to release theclutch and disconnect the follow-up mechanism 55 when the latter reachesthe high speed setting, the position of the cam 58 therefore remainingunchanged in the subsequent operation of the motor 45 that completes thecalibrating action. To this end, the circuit for energizing the clutchwinding extends from the battery through the normally closed parallelswitch 12, I3, the-switch 58 of the calibration relay 5'! and switchesI0 and II closure of the associated switches 10, ll. Dur-- ment of thelever 53 to the take oil position, the switch H will be held open by therelay 5i and the clutch in maintained engaged until the follow-upmechanism 55 is continued for operation of the engines at maximum ortake off speed. At this time, therelay 5i will become deenergized as theswitch 56 is opened by the cam 58 thereby closing the circuit forenergizing the clutch windings 64. The clutch is thus released so thatin the continued but short ensuing operation of the motor 45, which maybe necessary in order to bring all of the engines M and S to the sametake oil speed, the cam 58 will not be moved. As a result, thecalibrating adjustments of the engine speeds are eflfected while at thesame time leaving the follow-up mechanism 55 conditioned for properoperation when the automatic synchronizing control is restored or whenthe manual control is used to reduce the engine speeds after take off.During the latter adjustment, caused by energization of the relay 49,the switch is held open so that the clutch winding 64 remainsdeenergized and the follow-up mechanism thereby connected to theadjusting motor 45.

With the, calibrating control described above, all of the differentpower units may be brought precisely to the same speed by asimplemanipulation at the remote point of control. Such calibration iseffected in every instance during take off and as an incident thereto,the follow-up mechanism is left conditioned for proper operation duringsubsequent control for automatic synchronizin or readjustment of theengine speeds. Except'for the limit stops 25, the principal parts of thecalibratin control are located remotely from the engines and suchcontrol operates through the intermediary of the main actuating parts ofthe automatic synchronizing and manual speed adjusting controls. As aresult, the equipment required to be added in order to effect thecalibrating control is reduced to a minimum and is of simple characterand well suited to stand up under conditions encountered in multiengineair craft.

I claim as my invention:

1. Mechanism for selectively positioning a plurality of independentlymovable elements comprising individual self-synchronous reversibleelectric motors for actuating the respective elements, stops limitingthe movements of the respective elements in one direction tocorresponding limit positions, a self-synchronous rotary transmitter forenergizing all of said motors, a

motor driven operator for driving said transmitter, manually operablemeans for controlling the operation of said operator including a membermovable back and forth to select difierentspeed settings for saidelements, follow-up means driven by said operator through a releasableclutch for interrupting the operation of the operator when saidtransmitter has been turned to a position corresponding to the selectedposition of said member, supplemental means operable automatically as anincident to movement of said member to a predetermined position forcontinuing the operation of said operator and transmitters until all ofsaid elements have reached their respective limit stops, and means forreleasing said clutch when said manually movable member is in saidpredetermined position and the follow-up means reaches a correspondingposition.

2. Mechanism for selectively positioning a plurality of independentlymovable elements comprising individual electric motors for actuating therespective elements, stops limiting the movements of the respectiveelements in corresponding limit positions, a self-synchronous rotarytransmitter for energizing all of said motors, a motor driven operatorfor driving said transmitter, manually operable means for controllingthe operation of said operator including a member movable back and forthto select different speed settings for said elements, follow-up meansdriven by said operator through a releasable clutch for interrupting theoperation of the operator when said transmitter has been turned to aposition corresponding to the selected position of said member,supplemental manually operable control means for continuing theoperation of said operator and transmitters until all of said elementshave reached the respective limit stops, and means for releasing saidclutch when said member is disposed in a predetermined position and thefollow-up means reaches a corresponding position.

3. Mechanism for selectively positioning a plurality of independentlymovable devices comprising individual self-synchronous power actuatorsfor the respective devices, self-synchronous electrical transmittingmeans located at a remote point of control and associated with saidactuators for energizing the latter simultaneously, in dividual stopsfor limiting the adjustment of the respective devices inone direction,an electric motor for driving said transmitting means, means controllingthe energization of said motor including a member manually movabletoward and I away from a predetermined position, follow-up means drivenby said motor and normally operable to interrupt the operation thereofwhen said transmitting means has been moved a distance corresponding toa changed position of said memher. and supplemental means responsive tomovement of said member to said predetermined position and controllingsaid motor independently of said follow-up means to continue operationof said motor until each of said devices has reached its limit stop.

4. Mechanism for selectively positioning a. plurality of independentlymovable devices comprising individual self-synchronous power actuatorsfor the respective devices, self-synchronous electrical transmittingmeans located at a remote point of control and associated with saidactuators for energizing the latter simultaneously, individual stops forlimiting the adjustment of the respective devices in one direction, amotor for driving said transmitting means, means controlling theenergization of said motor including a member manually movable towardand away from a predetermined position, follow-up means driven by saidmotor and normally operable to interrupt the operation thereof when saidtransmitting means has been moved a distance corresponding to a changedposition of said member, and supplemental manually controllable meanscontrolling said motor independently of said follow-up means to continueoperation of said motor until each of said devices has reached its limitstop.

5. Mechanism for selectively positioning a plurality of independentlymovable devices comprising individual self-synchronous power actuatorsfor the respective devices, self-synchronous electrical transmittingmeans located at a remote point of control and associated with saidactuators for energizing the latter simultaneously, individual stops forlimiting the adjustment of the I the follow-up means is satisfied anduntil eachof said devices has reached its limit stop, and meansconditioned for operation by actuation of said supplemental means andoperable to release said clutch when the follow-up means reaches apredetermined position corresponding to the limit position of one ofsaid devices.

6. Mechanism for selectively positioning a plurality of independentlymovable devices comprising individual stops for limiting the adjustmentsof the respective devices in one direction, individual self-synchronouspower actuators tor the respective devices, self-synchronous electricaltransmitting means located at a remote point of control and associatedwith said actuators, a member manually movable back and forth to selectdiilerent settings of said devices, means controlled by said member formoving said transmitting means a distance corresponding to each changedp sition of said member, and supplemental means responsive to movementoi. said member to a predetermined position to continue the operation ofsaid transmitting means until all of said devices have reached theirrespective limit stops.

7. Mechanism for selectively positioning a plurality of independentlymovable devices comprising individual self-synchronous power actuatorsfor the respective devices, self-synchronous electrical transmittingmeans located at a remote Number point oi control and associated withsaid actuators for energizing the latter simultaneously,

individual stops for limiting the adjustment of 8; Mechanism forselectively positioning a plurality or independently movable devicescomprising individual self-synchronous power actuators tor therespective devices, self-synchronous electrical transmitting meansassociated with said actuators for energizing the latter simultaneously,a manually movable member, power driven means started in response to achange in theposition of said member, follow-up means for stopping saidtransmitting means after movement thereof through a correspondingdistance, individual stops for limiting the adjustment of the respectivedevices in one direction, and selectively controllable means forcontinuing the operation of said actuators after said follow-up meanshas been satisfled and until all of said devices have reached theirrespective limit stops.

GEORGE E. SORENSEN.

RWEBENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Name misc 2,412,605 Drake Dec. 17, 1946

